From a botanical perspective, lavender (Lavandula spp.) is a woody-based perennial subshrub. It does not spread by runners or stolons; instead, it grows outward from a central, often woody, crown. Over time, the center of the plant can become woody and less productive. The root system is fibrous but relatively shallow and can be quite dense. This growth pattern means that a mature lavender plant is actually a collection of many individual stems emerging from the root crown. For successful separation, it is crucial to understand that you are not cutting through a single taproot but carefully dividing these clustered stems and their attached fibrous roots into smaller, viable sections.
The plant's physiological state is paramount for successful transplantation. The ideal time to separate and transplant lavender is in the early spring, just as new, green growth begins to emerge at the base of the plant. At this point, the plant is exiting winter dormancy. Its energy reserves, stored in the roots and crown, are primed for rapid growth to support new shoots and roots. The cool, moist conditions of spring reduce transplant shock by minimizing water loss through the leaves (transpiration) while the new root system establishes itself. Dividing in the fall is possible in mild climates, but spring is universally preferred as it gives the plant an entire growing season to establish before facing winter stresses.
Begin by hydrating the parent plant thoroughly a day before the operation to ensure the roots and cells are turgid. Carefully dig around the entire plant's drip line (the area directly under the outer stems) and gently lift the entire root ball from the soil. Using a sharp, clean spade or knife, cleanly slice through the central crown to divide the plant into smaller sections. Each division must have a healthy portion of the root system—a mass of fibrous roots—and several healthy green stems or growth buds attached. Avoid creating divisions that are too small, as they lack the energy and root mass to recover efficiently. Tease apart the outer, younger sections of the plant; these are more vigorous and will establish faster than the old, woody center, which is often discarded.
Immediately after division, transplant the new sections to prevent the delicate roots from drying out. Prepare a planting site with very well-draining soil; lavender requires excellent drainage to avoid root rot. Amend heavy soil with generous amounts of gravel, sand, or grit. Plant each division at the same depth it was previously growing. Water it in thoroughly to settle the soil around the roots and eliminate air pockets. For the first few weeks, maintain consistently slightly moist (but never soggy) soil to encourage new root growth into the surrounding earth. Once new growth is evident, you can gradually reduce watering to encourage the deep, drought-tolerant root system that is characteristic of a healthy lavender plant. Avoid fertilizing immediately, as this can stress the plant; wait until it is actively growing.
